SIRIS, ALTO and NAS: Datto Windows Agent: Error: "Snapshot not in a good state - State 5 Error 0x00000028"

Issue

When you start a backup by using the Datto Windows Agent, you see a generic "Critical backup failure during data transfer" error in the device GUI. In the agent logs, you see, "Snapshot not in a good state - State 5 Error 0x00000028."

Environment

Datto Windows Agent 2.1 and above

Cause

The Copy on Write (COW) file for one or more volumes is highly fragmented, causing the backup to fail.

You'll see the following error in the Agent Logs from the Protect tab of the Datto device GUI:

Snapshot not in a good state - State 5 Error 0x00000028. Deleting snapshot set 801ade94-1ece-42b4-af67-dca42b2c9a6a